Twenty-four-hour energy expenditure and resting metabolic rate in obese, moderately obese, and control subjects.
Twenty-four-hour energy expenditure (24-EE), resting metabolic rate (RMR) and body composition were determined in 30 subjects from three groups; control (103 +/- 2% ideal body weight, n = 10), moderately obese (129 +/- 1% ideal body weight, n = 6), and obese (170 +/- 5% ideal body weight, n = 14) individuals. Twenty-four EE was measured in a comfortable airtight respiration chamber. When expressed as absolute values, both RMR and 24-EE were significantly increased in obese subjects when compared to normal weight subjects. The RMR was 7592 +/- 351 kJ/day in the obese, 6652 +/- 242 kJ/day in the moderately obese, and 6118 +/- 405 kJ/day in the controls. Mean 24-EE values were 10043 +/- 363, 9599 +/- 277, and 8439 +/- 432 kJ/day in the obese, moderately obese, and controls, respectively. The larger energy expenditure in the obese over 24 h was mainly due to a greater VO2 during the daylight hours. However, 92% of the larger 24-EE in the obese, compared to the control group, was accounted for by the higher RMR and only 8% by other factors such as the increased cost of moving the extra weight of the obese. The higher RMR and 24-EE in the obese was best related to the increased fat free mass.
D000328:Adult; D001481:Basal Metabolism; D001823:Body Composition; D002245:Carbon Dioxide / Q000097:blood; D002940:Circadian Rhythm; D004734:Energy Metabolism; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood / Q000378:metabolism*; D012890:Sleep / Q000502:physiology
D005230:Fatty Acids, Nonesterified; D002245:Carbon Dioxide